New Technique for Screening of Laccase-Mediators, 1997 Biological Sciences Symposium Proceedings

Developing an environmentally benign pulp bleaching process is imperative in the pulp and paper industry. A lactase-mediator system is one of the promising methods to constitute one step in such a bleaching process. However, several hurdles such as expenses of a lactase-mediator and effectiveness of the laccase-mediator system are hindering the commercialization of such a system for pulp bleaching. To fmd a cheaper and more effective lactase-mediator system, a method for fast screening of laccase mediators was established. Various categories of organic compounds were tested as laccase mediators. The relationship between structural characteristics of a mediator and the oxidation of a lignin p-O-4 dimer, l-(3,4-dimethoxyphenyl)-2-(2- methoxyphenoxy)propan- 1,3-diol (I), was discussed. A laccase-mediator system was also used for pulp bleaching. A crude laccase and various concentrations of l-HBT were investigated. Brightness and kappa number of the pulp were determined. The results from pulp bleaching were consistent with those from the screening system demonstrating that the lactase-mediator screening system was useful for predicting its efficiency for lignin degradation.